GPT-3.5 Turbo

OpenAI's widely-adopted cost-effective model released March 2023. Optimized for chat via Chat Completions API with natural language and code generation capabilities. Features 16K context window (20 pages of text). Significantly cheaper than GPT-4 family while maintaining solid performance for most common use cases. Priced at $0.50 per 1M input tokens and $1.50 per 1M output (60% cheaper than previous pricing). Enhanced with better steerability, improved function calling, and extended context. Widely deployed in production applications globally. GPT-4o-mini now recommended upgrade for better performance at similar cost.